“Pumps,” the man repeated. He didn’t have a London accent. It was a soft country accent, like a farmer. “All the tunnels underground used to have pumps in them, to keep the water out. With no one working them, the water’s coming up. City’s drowning, I reckon.”

“Where are you taking me?” said Sam.

The man smiled. “You’ll see.”

He picked Sam up again and trotted off.

It wasn’t far to the next station, but Sam still felt like he’d had enough. When they got there the man put Sam on the platform and climbed up after him. He took hold of Sam’s hand.

“Stick with me, kiddo,” he said, leading Sam along the platform. “We don’t want you getting lost.”

Sam looked at the station name. Bank. The tiles on either side of the sign made a shape of dragons. There were openings through to the platform on the other side, but they were barred by locked barriers. When they came to the last one, the man unlocked it and took Sam through, before locking it carefully behind him. This platform was identical to the other one, except there was a train standing at it. Small candles in glass jars on the ground gave a warm glow. There was the sound of a generator and the smell of gasoline fumes. The exit and way up to the station was at the end on the left, the opening crudely blocked with an old iron bed frame.

“Home sweet home,” said the man, and he went over to the train and banged on the side of one of the cars.

Presently the doors slid open and a woman appeared in the doorway. She was round and jolly looking, with a big woolly sweater like the man’s, and a long, wide skirt. She had a bush of graying reddish hair and a kindly face. She beamed at Sam when she saw him.

“And who have we got here, then?” she said.

“His name’s Sam,” said the man. “Found him up at King’s Cross, and I reckon he’s probably one hungry lad.”

“Come on in, come in.” The woman bustled back inside, and Sam followed.

The car had been fitted out as a living area, and it looked very cozy. There were flickering candles, curtains at the windows, rugs and cushions on the floor, and drapes over the seats. A makeshift double bed filled one part, and in the open area by two of the doors, the couple had even rigged up a stove. Sam noticed that there was a chimney above it that went up into the ventilation ducts in the station ceiling, exactly like the one Ben and Bernie had built at Waitrose.

“Now you sit yourself down, young man,” said the woman, “and I’ll get you some soup. How about that, eh? I’ll just move Orion.”